childcare in holidays payments

[Tracey1969]

i will be finishing a school run soon for a parent who i look after there 4 children but they still want me for holidays only starting from Sept. i told them they will have to pay a small fee for the places to be kept open as it is 4 children ages 10, 9, 6, and 4. Am i being greedy as i did tell them that i will loose alot of money if i only do holidays only and i could fill there places with children who want me every week. The parents don't want to pay me if i am not having there children in the week but want garrantted places and they said they will give me at least 4 weeks notice if they require me. i told them i don't work like that but unless they don't pay me a small fee in the week i can't garranttee there places. Any suggestions please i have had these children for 12 months now and i thought i had a good relationship with the parents up untill now as they have asked me to do cash in hand (i wont) but i told them this doesn't solve the situation as this is my business.